The present application relates to media stream management on the internet.
When communicating media over the internet, five problems arise: bandwidth management; hairpinning; backhauling; media path control; and equal access. These problems will be discussed below, such as in the context of Voice-over-Internet-Protocol (VoIP). It should be understood of course that the present application relates to any type of media stream management on the internet.
By way of background, the “Open Systems Interconnection” protocol (OSI) comprises a seven layer model: application (layer 7); presentation (layer 6); session (layer 5); transport (layer 4); network (layer 3); data link (layer 2); and physical (layer 1).
For VoIP, so-called “user agents” (UA) operating at the application layer send and receive information packets by use of the Session Internet Protocol (SIP), SDP, H.323, MGCP, Megaco etc. SIP and SDP are by far the most commonly used protocol for VoIP based communications.
Before discussing further the media communication problems of bandwidth, hairpinning, equal access, and backhauling, the following acronyms used hereafter are identified for convenience:                3GPP 3rd generation Partnership Project        AOR Address of Record        ASP Application Service Provider        AS Application Server        ATM Asynchronous Transfer Mode        BW Bandwidth        CAC Call Access Control        CDR Call Detail Record        CSCF Call/Session Control Function        DoS Denial of Service (attacks)        HTTP Hypertext Transport Protocol        IM Instant Messaging        ID Identification        IP Internet Protocol        ISP Internet Service Provider        IVR Interactive Voice Response        IXC Inter-Exchange Carrier        LSP Label Switched Path        MG Media Gateway        MIME Multi-Purpose Internet Mail Extensions        MM Media Management        MPLS Multi-Protocol Label Switching        MR Media Routing        MSC Multi-Protocol Session Controller        MSF R2 Multi-Service Switching Forum        NRX New Receive Address        P-CSCF Proxy Call Session Control Function        PDF Policy Decision Function        POP Point of Presence        PSTN Public Switched Telephone Network        QoS Quality of Service        RACF Resource and Admission Control Function        RBOC Regional Bell Operating Company        RTP Real-Time Transport Protocol        RTSP Real-Time Streaming Protocol        RX Receive Address/Port        SAP Session Announcement Protocol        SBC Session Border Controller        SDP Session Description Protocol        SIP Session Initiation Protocol        SLA Service Level Agreement        SRC Source        TCP Transmission Control Protocol        TISPAN TIPHON (Telecommunications and Internet Protocol Harmonization over Networks) and SPAN (Services and Protocols for Advanced Networks) (ETSI)        UDP Universal Datagram Protocol        VM Voice Mail        VoIP Voice over Internet Protocol        WWW World Wide Web        
First, the problem of bandwidth management will be discussed. According to the low-level design scheme, information to be communicated is broken down into discrete packets of information, and these packets are directed from an originating endpoint to a destination endpoint. A higher level protocol is used to establish a connection between the endpoints. Accordingly, a virtual communications link is established and a long message is broken down into multiple packets and sent by the sender. The receiving end collects these packets and reassembles them into the original long message. However, the individual packets that comprise the message may travel over different routes to reach the endpoint, depending on network availability, loading, etc.
When transmitting e-mail, web pages, and data files or the like, it is generally not crucial that data be transmitted in real-time, i.e., delays in the data transmission are generally acceptable if the intervening network is heavily loaded. However, with respect to real-time interactive communications, such as VoIP and videoconferences, excessive delay can make the communication unworkable. Therefore, for such real-time interactive media communications, properly allocating and managing the bandwidth is important. Also, as discussed hereafter, the problems of hairpinning, equal access, and backhauling need to be managed.
Now the problems known as “hairpinning”, “bandwidth management” “media path control”, “equal access” and “backhauling” will be explained.
Hairpinning describes the situation where the caller and callee are in the same network.
Bandwidth management is a problem where a network has to manage how bandwidth is allocated for multimedia sessions based on policies for network topology or network users. Bandwidth management is necessary in order to provide guaranteed QoS (Quality of Service) to sessions and media streams which are admitted in the network and to prevent sessions from being established through the network where bandwidth is not available (using policy). Bandwidth may be tracked on single networks or between networks.
Media Path Control is a problem where in order to control the QoS provided to a session media or to route the media through incompatible networks, the media stream needs to be routed through specific network elements (generally called media gateways or MGs). Media path is controlled independently from the path session signaling takes, especially in VoIP where the two paths are setup using different protocols (e.g. SIP for signaling and SDP for media).
Equal access is a regulatory requirement which allows a subscriber to access long distance services by dialing a special code on his phone before dialing the intended recipient, thereby choosing a carrier of his choice. The user's service provider thus has to open up access to his physical infrastructure or service to third party long distance providers. For VoIP and other Internet based applications this may mean that the session signaling (that is, a signal to begin a call such as “INVITE”) and/or media stream must be routed to a third party long distance provider.
Media backhauling is a problem where media is upstreamed to the provider's core network where the service offered is controlled instead of being routed through a shorter path between the subscribers. The shorter path, which is preferred, is either a direct path between the subscribers of through local servers located close to the subscribers who do not have the service intelligence.
In attempting to deal with the aforementioned and described media stream management problems of bandwidth, hairpinning, media path control, equal access, and/or backhauling, it has previously been known to provide at least the following types of media management:                RACF element in TISPAN architecture (provides bandwidth management);        MIDCOM (IETF) framework specifies some form of media path control;        Bandwidth Manager element in MSF R2 Architecture (provides bandwidth management;        Session Border Controllers today integrating or coupling some forms of media management.        